I want to run a process that will make a table with lots of roads into distinct table of roads and than calculate the center of each road.

How can I auto merge segments with same name to one long segment ?

Attached example of 1 road built from 3 different segments , I want to make it one road and have it center point. (so I can zoom on it from OpenLayers)

enter image description here

  • Do you need the values of the center point or do you need it for styling purposes? A marker line style has the option to put a marker on the line center. – underdark Dec 20 '12 at 11:51
  • I need it so I can setCenter on street using OpenLayers from a dropdownlist that will read the data after I export it to db. – Alophind Dec 20 '12 at 13:11

To auto-merge features based on attributes I recommend the Dissolve-tool (Vector -> Geoprocessing Tools).


Appearently dissolve does not work on lines... You will have to use the Vector-> Geometry Tools-> Singleparts to Multipart tool.

  • I'm trying to use the tool but the Combo box of Input vector layer won't open (like its empty) while I have only 1 vector layer (Layer -> Add Vector Layer) in the project. Any idea why ? – Alophind Dec 20 '12 at 10:29
  • What version of ftools/GDAL tolls do you have? (Check the plugin-installer) – GR_ Dec 20 '12 at 10:35
  • GDalTool ver 1.2.29 QGIS 1.8.0 – Alophind Dec 20 '12 at 11:07
  • Ftools 0.6.2 . Any idea ?! – Alophind Dec 20 '12 at 11:08
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    I'm kinda running out of ideas... you could save the shape as a new file and try again, maybe that does the trick. Reinstalling ftools/GDAL tools is also an option. – GR_ Dec 20 '12 at 11:13

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